> RF is the magic grey beards part, but can be quickly solved with off the shelf parts.
What do you mean by "off the shelf parts"? A competitive phone chipset is going to have integrated RF and digital baseband. Because of size constraints, you can't mix and match ICs and have any hope of fitting into a small form factor.
I mean RF is a solved problem, there are no secrets in that part of modem design anymore. You can pick an off the shelf cable modem RF frontend (AD9866 etc) and implement 4G baseband. What you will need is experienced software people and IP rights.
On a tangential note Intel totally screwed DOCSIS modem chipsets, after taking over TI's Puma product line, by stuffing it with x86 cores and assigning work experience students to write firmware, after all everyone can code x86, right? :) Puma 6/7 can be DOSed by as little as 10KB/s stream. Supposedly there are firmware fixes, but from what I gather they just move critical processing tasks from integrated x86 cores to external ARM SoC - prevents DOSing, but latency issues persist.
I think he means that there will be a few components that will be able to develop that IP for you. That is certainly the case for PLLs and other analog bits of digital designs.
What do you mean by "off the shelf parts"? A competitive phone chipset is going to have integrated RF and digital baseband. Because of size constraints, you can't mix and match ICs and have any hope of fitting into a small form factor.